PathCompiler.java
package com.jayway.jsonpath.internal.path;
import com.jayway.jsonpath.InvalidPathException;
import com.jayway.jsonpath.Predicate;
import com.jayway.jsonpath.internal.CharacterIndex;
import com.jayway.jsonpath.internal.Path;
import com.jayway.jsonpath.internal.Utils;
import com.jayway.jsonpath.internal.filter.FilterCompiler;
import com.jayway.jsonpath.internal.function.ParamType;
import com.jayway.jsonpath.internal.function.Parameter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import static java.lang.Character.isDigit;
import static java.util.Arrays.asList;
public class PathCompiler {
private static final char DOC_CONTEXT = '$';
private static final char EVAL_CONTEXT = '@';
private static final char OPEN_SQUARE_BRACKET = '[';
private static final char CLOSE_SQUARE_BRACKET = ']';
private static final char OPEN_PARENTHESIS = '(';
private static final char CLOSE_PARENTHESIS = ')';
private static final char OPEN_BRACE = '{';
private static final char CLOSE_BRACE = '}';
private static final char WILDCARD = '*';
private static final char PERIOD = '.';
private static final char SPACE = ' ';
private static final char TAB = '\t';
private static final char CR = '\r';
private static final char LF = '\n';
private static final char BEGIN_FILTER = '?';
private static final char COMMA = ',';
private static final char SPLIT = ':';
private static final char MINUS = '-';
private static final char SINGLE_QUOTE = '\'';
private static final char DOUBLE_QUOTE = '"';
private final LinkedList<Predicate> filterStack;
private final CharacterIndex path;
private PathCompiler(String path, LinkedList<Predicate> filterStack){
this(new CharacterIndex(path), filterStack);
}
private PathCompiler(CharacterIndex path, LinkedList<Predicate> filterStack){
this.filterStack = filterStack;
this.path = path;
}
private Path compile() {
RootPathToken root = readContextToken();
return new CompiledPath(root, root.getPathFragment().equals("$"));
}
public static Path compile(String path, final Predicate... filters) {
try {
CharacterIndex ci = new CharacterIndex(path);
ci.trim();
if(!( ci.charAt(0) == DOC_CONTEXT) && !( ci.charAt(0) == EVAL_CONTEXT)){
ci = new CharacterIndex("$." + path);
ci.trim();
}
if(ci.lastCharIs('.')){
fail("Path must not end with a '.' or '..'");
}
LinkedList<Predicate> filterStack = new LinkedList<Predicate>(asList(filters));
return new PathCompiler(ci, filterStack).compile();
} catch (Exception e) {
InvalidPathException ipe;
if (e instanceof InvalidPathException) {
ipe = (InvalidPathException) e;
} else {
ipe = new InvalidPathException(e);
}
throw ipe;
}
}
private void readWhitespace() {
while (path.inBounds()) {
char c = path.currentChar();
if (!isWhitespace(c)) {
break;
}
path.incrementPosition(1);
}
}
private Boolean isPathContext(char c) {
return (c == DOC_CONTEXT || c == EVAL_CONTEXT);
}
//[$ | @]
private RootPathToken readContextToken() {
readWhitespace();
if (!isPathContext(path.currentChar())) {
throw new InvalidPathException("Path must start with '$' or '@'");
}
RootPathToken pathToken = PathTokenFactory.createRootPathToken(path.currentChar());
if (path.currentIsTail()) {
return pathToken;
}
path.incrementPosition(1);
if(path.currentChar() != PERIOD && path.currentChar() != OPEN_SQUARE_BRACKET){
fail("Illegal character at position " + path.position() + " expected '.' or '['");
}
PathTokenAppender appender = pathToken.getPathTokenAppender();
readNextToken(appender);
return pathToken;
}
//
//
//
private boolean readNextToken(PathTokenAppender appender) {
char c = path.currentChar();
switch (c) {
case OPEN_SQUARE_BRACKET:
if (!readBracketPropertyToken(appender) && !readArrayToken(appender) && !readWildCardToken(appender)
&& !readFilterToken(appender) && !readPlaceholderToken(appender)) {
fail("Could not parse token starting at position " + path.position() + ". Expected ?, ', 0-9, * ");
}
return true;
case PERIOD:
if (!readDotToken(appender)) {
fail("Could not parse token starting at position " + path.position());
}
return true;
case WILDCARD:
if (!readWildCardToken(appender)) {
fail("Could not parse token starting at position " + path.position());
}
return true;
default:
if (!readPropertyOrFunctionToken(appender)) {
fail("Could not parse token starting at position " + path.position());
}
return true;
}
}
//
// . and ..
//
private boolean readDotToken(PathTokenAppender appender) {
if (path.currentCharIs(PERIOD) && path.nextCharIs(PERIOD)) {
appender.appendPathToken(PathTokenFactory.crateScanToken());
path.incrementPosition(2);
} else if (!path.hasMoreCharacters()) {
throw new InvalidPathException("Path must not end with a '.");
} else {
path.incrementPosition(1);
}
if(path.currentCharIs(PERIOD)){
throw new InvalidPathException("Character '.' on position " + path.position() + " is not valid.");
}
return readNextToken(appender);
}
//
// fooBar or fooBar()
//
private boolean readPropertyOrFunctionToken(PathTokenAppender appender) {
if (path.currentCharIs(OPEN_SQUARE_BRACKET) || path.currentCharIs(WILDCARD) || path.currentCharIs(PERIOD) || path.currentCharIs(SPACE)) {
return false;
}
int startPosition = path.position();
int readPosition = startPosition;
int endPosition = 0;
boolean isFunction = false;
while (path.inBounds(readPosition)) {
char c = path.charAt(readPosition);
if (c == SPACE) {
throw new InvalidPathException("Use bracket notion ['my prop'] if your property contains blank characters. position: " + path.position());
}
else if (c == PERIOD || c == OPEN_SQUARE_BRACKET) {
endPosition = readPosition;
break;
}
else if (c == OPEN_PARENTHESIS) {
isFunction = true;
endPosition = readPosition;
break;
}
readPosition++;
}
if (endPosition == 0) {
endPosition = path.length();
}
List<Parameter> functionParameters = null;
if (isFunction) {
int parenthesis_count = 1;
for(int i = readPosition + 1; i < path.length(); i++){
if (path.charAt(i) == CLOSE_PARENTHESIS)
parenthesis_count--;
else if (path.charAt(i) == OPEN_PARENTHESIS)
parenthesis_count++;
if (parenthesis_count == 0)
break;
}
if (parenthesis_count != 0){
String functionName = path.subSequence(startPosition, endPosition).toString();
throw new InvalidPathException("Arguments to function: '" + functionName + "' are not closed properly.");
}
if (path.inBounds(readPosition+1)) {
// read the next token to determine if we have a simple no-args function call
char c = path.charAt(readPosition + 1);
if (c != CLOSE_PARENTHESIS) {
path.setPosition(endPosition+1);
// parse the arguments of the function - arguments that are inner queries or JSON document(s)
String functionName = path.subSequence(startPosition, endPosition).toString();
functionParameters = parseFunctionParameters(functionName);
} else {
path.setPosition(readPosition + 1);
}
}
else {
path.setPosition(readPosition);
}
}
else {
path.setPosition(endPosition);
}
String property = path.subSequence(startPosition, endPosition).toString();
if(isFunction){
appender.appendPathToken(PathTokenFactory.createFunctionPathToken(property, functionParameters));
} else {
appender.appendPathToken(PathTokenFactory.createSinglePropertyPathToken(property, SINGLE_QUOTE));
}
return path.currentIsTail() || readNextToken(appender);
}
/**
* Parse the parameters of a function call, either the caller has supplied JSON data, or the caller has supplied
* another path expression which must be evaluated and in turn invoked against the root document. In this tokenizer
* we're only concerned with parsing the path thus the output of this function is a list of parameters with the Path
* set if the parameter is an expression. If the parameter is a JSON document then the value of the cachedValue is
* set on the object.
*
* Sequence for parsing out the parameters:
*
* This code has its own tokenizer - it does some rudimentary level of lexing in that it can distinguish between JSON block parameters
* and sub-JSON blocks - it effectively regex's out the parameters into string blocks that can then be passed along to the appropriate parser.
* Since sub-jsonpath expressions can themselves contain other function calls this routine needs to be sensitive to token counting to
* determine the boundaries. Since the Path parser isn't aware of JSON processing this uber routine is needed.
*
* Parameters are separated by COMMAs ','
*
* <pre>
* doc = {"numbers": [1,2,3,4,5,6,7,8,9,10]}
*
* $.sum({10}, $.numbers.avg())
* </pre>
*
* The above is a valid function call, we're first summing 10 + avg of 1...10 (5.5) so the total should be 15.5
*
* @return
* An ordered list of parameters that are to processed via the function. Typically functions either process
* an array of values and/or can consume parameters in addition to the values provided from the consumption of
* an array.
*/
private List<Parameter> parseFunctionParameters(String funcName) {
ParamType type = null;
// Parenthesis starts at 1 since we're marking the start of a function call, the close paren will denote the
// last parameter boundary
int groupParen = 1, groupBracket = 0, groupBrace = 0, groupQuote = 0;
boolean endOfStream = false;
char priorChar = 0;
List<Parameter> parameters = new ArrayList<Parameter>();
StringBuilder parameter = new StringBuilder();
while (path.inBounds() && !endOfStream) {
char c = path.currentChar();
path.incrementPosition(1);
// we're at the start of the stream, and don't know what type of parameter we have
if (type == null) {
if (isWhitespace(c)) {
continue;
}
if (c == OPEN_BRACE || isDigit(c) || DOUBLE_QUOTE == c || MINUS == c) {
type = ParamType.JSON;
}
else if (isPathContext(c)) {
type = ParamType.PATH; // read until we reach a terminating comma and we've reset grouping to zero
}
}
switch (c) {
case DOUBLE_QUOTE:
if (priorChar != '\\' && groupQuote > 0) {
groupQuote--;
}
else {
groupQuote++;
}
break;
case OPEN_PARENTHESIS:
groupParen++;
break;
case OPEN_BRACE:
groupBrace++;
break;
case OPEN_SQUARE_BRACKET:
groupBracket++;
break;
case CLOSE_BRACE:
if (0 == groupBrace) {
throw new InvalidPathException("Unexpected close brace '}' at character position: " + path.position());
}
groupBrace--;
break;
case CLOSE_SQUARE_BRACKET:
if (0 == groupBracket) {
throw new InvalidPathException("Unexpected close bracket ']' at character position: " + path.position());
}
groupBracket--;
break;
// In either the close paren case where we have zero paren groups left, capture the parameter, or where
// we've encountered a COMMA do the same
case CLOSE_PARENTHESIS:
groupParen--;
//CS304 Issue link: https://github.com/json-path/JsonPath/issues/620
if (0 > groupParen || priorChar == '(') {
parameter.append(c);
}
case COMMA:
// In this state we've reach the end of a function parameter and we can pass along the parameter string
// to the parser
if ((0 == groupQuote && 0 == groupBrace && 0 == groupBracket
&& ((0 == groupParen && CLOSE_PARENTHESIS == c) || 1 == groupParen))) {
endOfStream = (0 == groupParen);
if (null != type) {
Parameter param = null;
switch (type) {
case JSON:
// parse the json and set the value
param = new Parameter(parameter.toString());
break;
case PATH:
LinkedList<Predicate> predicates = new LinkedList<>();
PathCompiler compiler = new PathCompiler(parameter.toString(), predicates);
param = new Parameter(compiler.compile());
break;
}
if (null != param) {
parameters.add(param);
}
parameter.delete(0, parameter.length());
type = null;
}
}
break;
}
if (type != null && !(c == COMMA && 0 == groupBrace && 0 == groupBracket && 1 == groupParen)) {
parameter.append(c);
}
priorChar = c;
}
if (0 != groupBrace || 0 != groupParen || 0 != groupBracket) {
throw new InvalidPathException("Arguments to function: '" + funcName + "' are not closed properly.");
}
return parameters;
}
private boolean isWhitespace(char c) {
return (c == SPACE || c == TAB || c == LF || c == CR);
}
//
// [?], [?,?, ..]
//
private boolean readPlaceholderToken(PathTokenAppender appender) {
if (!path.currentCharIs(OPEN_SQUARE_BRACKET)) {
return false;
}
int questionmarkIndex = path.indexOfNextSignificantChar(BEGIN_FILTER);
if (questionmarkIndex == -1) {
return false;
}
char nextSignificantChar = path.nextSignificantChar(questionmarkIndex);
if (nextSignificantChar != CLOSE_SQUARE_BRACKET && nextSignificantChar != COMMA) {
return false;
}
int expressionBeginIndex = path.position() + 1;
int expressionEndIndex = path.nextIndexOf(expressionBeginIndex, CLOSE_SQUARE_BRACKET);
if (expressionEndIndex == -1) {
return false;
}
String expression = path.subSequence(expressionBeginIndex, expressionEndIndex).toString();
String[] tokens = expression.split(",");
if (filterStack.size() < tokens.length) {
throw new InvalidPathException("Not enough predicates supplied for filter [" + expression + "] at position " + path.position());
}
Collection<Predicate> predicates = new ArrayList<Predicate>();
for (String token : tokens) {
token = token != null ? token.trim() : null;
if (!"?".equals(token == null ? "" : token)) {
throw new InvalidPathException("Expected '?' but found " + token);
}
predicates.add(filterStack.pop());
}
appender.appendPathToken(PathTokenFactory.createPredicatePathToken(predicates));
path.setPosition(expressionEndIndex + 1);
return path.currentIsTail() || readNextToken(appender);
}
//
// [?(...)]
//
private boolean readFilterToken(PathTokenAppender appender) {
if (!path.currentCharIs(OPEN_SQUARE_BRACKET) && !path.nextSignificantCharIs(BEGIN_FILTER)) {
return false;
}
int openStatementBracketIndex = path.position();
int questionMarkIndex = path.indexOfNextSignificantChar(BEGIN_FILTER);
if (questionMarkIndex == -1) {
return false;
}
int openBracketIndex = path.indexOfNextSignificantChar(questionMarkIndex, OPEN_PARENTHESIS);
if (openBracketIndex == -1) {
return false;
}
int closeBracketIndex = path.indexOfClosingBracket(openBracketIndex, true, true);
if (closeBracketIndex == -1) {
return false;
}
if (!path.nextSignificantCharIs(closeBracketIndex, CLOSE_SQUARE_BRACKET)) {
return false;
}
int closeStatementBracketIndex = path.indexOfNextSignificantChar(closeBracketIndex, CLOSE_SQUARE_BRACKET);
String criteria = path.subSequence(openStatementBracketIndex, closeStatementBracketIndex + 1).toString();
Predicate predicate = FilterCompiler.compile(criteria);
appender.appendPathToken(PathTokenFactory.createPredicatePathToken(predicate));
path.setPosition(closeStatementBracketIndex + 1);
return path.currentIsTail() || readNextToken(appender);
}
//
// [*]
// *
//
private boolean readWildCardToken(PathTokenAppender appender) {
boolean inBracket = path.currentCharIs(OPEN_SQUARE_BRACKET);
if (inBracket && !path.nextSignificantCharIs(WILDCARD)) {
return false;
}
if (!path.currentCharIs(WILDCARD) && path.isOutOfBounds(path.position() + 1)) {
return false;
}
if (inBracket) {
int wildCardIndex = path.indexOfNextSignificantChar(WILDCARD);
if (!path.nextSignificantCharIs(wildCardIndex, CLOSE_SQUARE_BRACKET)) {
int offset = wildCardIndex + 1;
throw new InvalidPathException("Expected wildcard token to end with ']' on position " + offset);
}
int bracketCloseIndex = path.indexOfNextSignificantChar(wildCardIndex, CLOSE_SQUARE_BRACKET);
path.setPosition(bracketCloseIndex + 1);
} else {
path.incrementPosition(1);
}
appender.appendPathToken(PathTokenFactory.createWildCardPathToken());
return path.currentIsTail() || readNextToken(appender);
}
//
// [1], [1,2, n], [1:], [1:2], [:2]
//
private boolean readArrayToken(PathTokenAppender appender) {
if (!path.currentCharIs(OPEN_SQUARE_BRACKET)) {
return false;
}
char nextSignificantChar = path.nextSignificantChar();
if (!isDigit(nextSignificantChar) && nextSignificantChar != MINUS && nextSignificantChar != SPLIT) {
return false;
}
int expressionBeginIndex = path.position() + 1;
int expressionEndIndex = path.nextIndexOf(expressionBeginIndex, CLOSE_SQUARE_BRACKET);
if (expressionEndIndex == -1) {
return false;
}
String expression = path.subSequence(expressionBeginIndex, expressionEndIndex).toString().trim();
if ("*".equals(expression)) {
return false;
}
//check valid chars
for (int i = 0; i < expression.length(); i++) {
char c = expression.charAt(i);
if (!isDigit(c) && c != COMMA && c != MINUS && c != SPLIT && c != SPACE) {
return false;
}
}
boolean isSliceOperation = expression.contains(":");
if (isSliceOperation) {
ArraySliceOperation arraySliceOperation = ArraySliceOperation.parse(expression);
appender.appendPathToken(PathTokenFactory.createSliceArrayPathToken(arraySliceOperation));
} else {
ArrayIndexOperation arrayIndexOperation = ArrayIndexOperation.parse(expression);
appender.appendPathToken(PathTokenFactory.createIndexArrayPathToken(arrayIndexOperation));
}
path.setPosition(expressionEndIndex + 1);
return path.currentIsTail() || readNextToken(appender);
}
//
// ['foo']
//
private boolean readBracketPropertyToken(PathTokenAppender appender) {
if (!path.currentCharIs(OPEN_SQUARE_BRACKET)) {
return false;
}
char potentialStringDelimiter = path.nextSignificantChar();
if (potentialStringDelimiter != SINGLE_QUOTE && potentialStringDelimiter != DOUBLE_QUOTE) {
return false;
}
List<String> properties = new ArrayList<String>();
int startPosition = path.position() + 1;
int readPosition = startPosition;
int endPosition = 0;
boolean inProperty = false;
boolean inEscape = false;
boolean lastSignificantWasComma = false;
while (path.inBounds(readPosition)) {
char c = path.charAt(readPosition);
if(inEscape){
inEscape = false;
} else if('\\' == c){
inEscape = true;
} else if (c == CLOSE_SQUARE_BRACKET && !inProperty) {
if (lastSignificantWasComma){
fail("Found empty property at index "+readPosition);
}
break;
} else if (c == potentialStringDelimiter) {
if (inProperty) {
char nextSignificantChar = path.nextSignificantChar(readPosition);
if (nextSignificantChar != CLOSE_SQUARE_BRACKET && nextSignificantChar != COMMA) {
fail("Property must be separated by comma or Property must be terminated close square bracket at index "+readPosition);
}
endPosition = readPosition;
String prop = path.subSequence(startPosition, endPosition).toString();
properties.add(Utils.unescape(prop));
inProperty = false;
} else {
startPosition = readPosition + 1;
inProperty = true;
lastSignificantWasComma = false;
}
} else if (c == COMMA && !inProperty) {
if (lastSignificantWasComma){
fail("Found empty property at index "+readPosition);
}
lastSignificantWasComma = true;
}
readPosition++;
}
if (inProperty){
fail("Property has not been closed - missing closing " + potentialStringDelimiter);
}
int endBracketIndex = path.indexOfNextSignificantChar(endPosition, CLOSE_SQUARE_BRACKET);
if(endBracketIndex == -1) {
fail("Property has not been closed - missing closing ]");
}
endBracketIndex++;
path.setPosition(endBracketIndex);
appender.appendPathToken(PathTokenFactory.createPropertyPathToken(properties, potentialStringDelimiter));
return path.currentIsTail() || readNextToken(appender);
}
public static boolean fail(String message) {
throw new InvalidPathException(message);
}
}